What is Time to First Byte (TTFB)?
Time to First Byte (TTFB) measures how long it takes for a browser to receive the first byte of a page from the server after requesting it. It captures the server response time, including any redirects, DNS lookup, connection setup and the time the server spends generating the page. TTFB is not itself a Core Web Vital, but it sets the ceiling on the others: a slow first byte delays everything that follows. A good TTFB is generally 800 milliseconds or less.
Time to First Byte (TTFB), explained properly.
What TTFB actually measures
TTFB is the gap between a browser asking for a page and the first byte of that page arriving. It rolls up several steps: resolving the domain, establishing the connection, any redirects along the way, and, usually the biggest part, the time the server spends building the response before it sends anything. Because nothing can render until that first byte lands, TTFB is the foundation everything else in page speed sits on. It can be measured in the lab and, more meaningfully, on real users.
Why TTFB matters
TTFB sets the ceiling for Largest Contentful Paint and the rest of the loading experience: if the server takes a second to respond, the fastest possible LCP is already a second behind before the browser has done anything. It is where a lot of quiet, structural waste hides, on slow hosting, uncached database queries, or a chain of redirects, and it is often invisible in a front-end audit that only looks at the page once it arrives. Fixing it lifts every downstream metric at once, which is why we check it early.
How TTFB is improved
Improving TTFB is server and delivery work: faster or better-configured hosting, caching so the server is not rebuilding the same page on every request, a content delivery network to serve users closer to them, and removing redirect chains that add round trips before the real response. On sites we build and host, this is ours to own end to end; on sites we did not build, we diagnose the cause and are clear about which fixes sit with your developers or host, and work alongside them.
Time to First Byte (TTFB): common questions.
What is a good TTFB?
Generally 800 milliseconds or less is considered good. Above that, the server is delaying everything that follows, so it is usually worth fixing before chasing front-end metrics.
Is TTFB a Core Web Vital?
No, it is not one of the three Core Web Vitals, but it sets the ceiling on them. A slow first byte delays Largest Contentful Paint and the whole loading experience, so it is a foundational metric.
How do I improve TTFB?
Through server and delivery work: faster or better-configured hosting, caching so pages are not rebuilt on every request, a CDN to serve users closer to them, and removing redirect chains that add round trips.